This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal of the studies in this project is to obtain in vivo confirmation of the potential antiparkinsonian effects of blockade of NR2D-type NMDA receptors in an animal model of Parkinson's disease, the 6-OH-dopamine-lesioned rat. These agents are most likely to work by blocking NR2D receptors in the subthalamic nucleus, a structure which is overactive in Parkinson's disease. NR2D receptor blockade may act to normalize the activity in this nucleus. To test this hypothesis, three experiments were planned: (1) To establish the concentration-effect curve for inhibition of native NR2D-containing NMDA receptors in subthalamic neurons by our best NR2D-selective antagonist. The combination of this data with in vivo pharmacokinetic data will allow us to estimate receptor occupancy as a function of administered dose. (2) To determine the NR2D protein distribution using immunohistochemistry in normal rats and rats treated with 6-OH-dopamine to confirm that NR2D receptors are present in this animal model of Parkinson's disease. (3) To evaluate the ability of selective blockade of NR2D-containing receptors in basal ganglia neurons to alter motor behavior in 6-OHDA-lesioned animals. This project was completed and publications of results are in preparation.